So is there actually a reason to use gpSP-J instead of Kai? Or was the OP just being extremely stubborn? I don't understand why you would want to go through the hassle of changing the language of a Japanese emulator when the English version (Kai) works just as well... Unless there's something I'm not seeing here.

So is there actually a reason to use gpSP-J instead of Kai? Or was the OP just being extremely stubborn? I don't understand why you would want to go through the hassle of changing the language of a Japanese emulator when the English version (Kai) works just as well... Unless there's something I'm not seeing here.

There are some sound stuttering issues with certain roms using Kai, and the previous release of gpSP-J fixed these issues.

There is no official changelog, so there's no way of knowing what else was optimized in this latest release, unless you test the emulator and notice any improvements with certain games.